How to generate random string using PHP

Generate random, unique, alphanumeric strings using PHP.

Example:

EA070
aBX32gTf

Method 1:

The first method is the easiest to understand. It can be implemented as follows:

- Store all possible letters into a string.

- Generates a random index from 0 to string length - 1.

- Prints the letter at that index.

- Perform this step n times (where n is the length of the desired string).

The program code is as follows:

<?php 
$n=10; 
function getName($n) { 
    $characters = &#39;0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ&#39;; 
    $randomString = &#39;&#39;; 
  
    for ($i = 0; $i < $n; $i++) { 
        $index = rand(0, strlen($characters) - 1); 
        $randomString .= $characters[$index]; 
    } 
  
    return $randomString; 
} 
  
echo getName($n); 
?>

Output 1:

3HDrSOvRIs

Output 2:

lipHh

Method 2: Use hash function

PHP has some functions, such as md5(), sha1() and hash(), which can be used to hash strings according to certain algorithms (such as "sha1", "sha256", "md5", etc.) Hope to deal with it. All these functions take a string as argument and output an Alpha-Numeric hash string.

Use the rand() function to generate random numbers.

Hash it using one of the above functions.

Program 1:

<?php 
$str=rand(); 
$result = md5($str); 
echo $result; 
?>

Output 1:

2e437510c181dd2ae100fc1661a445d4

Output 2:

256394010059991a71ea05e5d859d2be

Program 2:

<?php 
$str=rand(); 
$result = sha1($str); 
echo $result; 
?>

Output 1:

6eadd9b2c4389d9b109b3b869f66aab5d8f9420a

Output 2:

ca2d3c0993ab87e842d0a7a01f319aca6c587a87

Program 3:

<?php 
$str = rand(); 
$result = hash("sha256", $str); 
echo $result; 
?>

Output 1:

2a41cbc8cc11f8c8d0eb54210fe524748b4def1c5b04fcf18c2d5972e24d11c2

Output 2:

291144c1cbba4de0bf199d37ee265ac95cc2e44e80fd2642b22a6e8ef2f42a39

Note : Above All functions are hash functions, so the resulting string length will always depend on the algorithm used, but it will always remain the same for the algorithm. So if you want to generate a fixed length string, you can truncate the generated string or concatenate it with another string as needed.

Method 3:

Use the uniqid() function. The uniqid() function in PHP is a built-in function used to generate a unique ID based on the current time (microseconds). By default, it returns a unique string 13 characters long.

Program:

<?php  
$result = uniqid();   
echo $result; 
?>

Output 1:

5bdd0b74e9a6c

Output 2:

5bdd0bbc200c4

Note: All the above methods are based on rand () and uniqid() functions. These functions are not cryptographically secure random generators. Therefore, it is recommended that these methods be avoided if the degree of randomness affects the security of the application.

Method 4:

Use the random_bytes() function. (Cryptographically Secure) The random_bytes() function generates cryptographically secure pseudo-random bytes, which can later be converted to hexadecimal format using the bin2hex() function.

Program:

<?php  
$n = 20; 
$result = bin2hex(random_bytes($n)); 
echo $result; 
?>

Output 1:

235aed08a01468f90fa726bd56319fb893967da8

Output 2:

508b84494cdf31bec01566d12a924c75d4baed39

This article is an introduction to the method of generating random strings in PHP. I hope Help those in need!

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